2021 Nissan Altima Problems

What owners report

Complaints on the 2021 Altima most often describe the automatic emergency braking and forward radar system engaging or warning when nothing is in the path, plus door lock actuators that stop responding to the fob or door buttons. Owners also report brake-pedal concerns and, on higher-mileage cars, engine noise and debris found in the oil pan. Many of the driver-assistance complaints arrive early in ownership, while lock and brake reports come in across a wide mileage range.

1. 1
   Forward collision avoidance

   Automatic emergency braking engages with nothing ahead

   • 15 complaints (21%)
   • typically at 2.9 yrs old
   • 2 mention a crash, fire or injury
   • filed 2021–2026

   Owners describe the car braking on its own or flashing collision warnings when the road ahead is clear, sometimes at highway speed, in rain, near an overpass or railway crossing, or when reversing. Several say the forward radar or front sensor was replaced and the warnings returned, and some were told by the dealer that no fault could be duplicated. Others report the AEB or forward collision warning lights coming on with a malfunction message instead of braking. Often described at low mileage, some under 10,000 to 17,000 miles, and in rain or low-light conditions.

   4 related service bulletins

   What to check: Ask whether any software update or sensor replacement for the AEB/forward collision system has been done, and test-drive in traffic and in rain to see whether warnings appear. Note whether the radar grille area is clean and undamaged.

   2 excerpts from owner complaints in NHTSA records

   “On two separate occasions my vehicle stopped on its own. Once while doing roughly 35mph the brakes applied on their own and the car stopped immediately. The second time I was at a.traffic light that had just turned green as I began to accelerate the brakes locked up and the car stopped immediately. What are my options regarding this issue.that I am having?”

   NHTSA complaint #11533878, filed 2023-07

   “My car is supposed to have an automatic braking system/collision detection. Two cars in front of me slammed on their brakes and the car in front of me slammed on his brake, and I didn't have enough time to react. I totalled my car, but my car is supposed to have a safety feature that automatically brakes. The faulty automatic braking didn't engage as it should have.”

   NHTSA complaint #11749014, filed 2026-07
2. 2
   Electrical system

   Door lock actuators stop working

   • 14 complaints (20%)
   • median 2,000 mi at 1.3 yrs old (1 states mileage, few)
   • 1 mention a crash, fire or injury
   • filed 2021–2026

   Owners report one or more power door locks quitting, usually starting with a rear door, so the door will not lock or unlock with the fob or the door button and has to be worked manually. Some describe the car not locking automatically while driving, or a locked door that would not open from inside. Complaints say the dealer replaced individual actuators, and some owners paid for the repairs themselves. Reported from a few thousand miles up through several years of ownership, with several owners noticing it after 2024.

   What to check: Lock and unlock every door with the fob and the interior buttons, and check that the automatic locking while driving works on all four doors.

   2 excerpts from owner complaints in NHTSA records

   “Rear door locks both do not work other than manually locking. Reported incidents online show many others have had newer Nissan vehicles like our 2021 Nissan Altima with the same issue, some have been locked in the car and had to climb out the window and others said the door unlocked and opened while driving. This is a big concern for me as a mom who has a son driving this car, the entire reason was that the safety ratings were good on this AWD full size 2021 vehicle. …”

   NHTSA complaint #11748567, filed 2026-07

   “Purchased the car in June of 2024 with around 33,000 miles. I thought the doors were locked and someone was able to just open my back door when my car was unattended in a store parking lot; the car was supposed to be locked. Lights and horn started going off. Being a female with a child this is a very scary issue. The idea that anyone can get in when you think the doors are locked or vice versa, in the event of an emergency no one can get in because the doors dont unlock. …”

   NHTSA complaint #11640747, filed 2025-02
3. 3
   Brakes

   Brake pedal feels weak or fails to stop the car

   • 10 complaints (14%)
   • median 42,897 mi at 4.1 yrs old (4 state mileage, few)
   • 3 mention a crash, fire or injury
   • filed 2021–2026

   Complaints describe the brake pedal going down without the car slowing as expected, sometimes in rental or higher-mileage cars, and one owner reported a crash at low speed. Others mention a scraping or grinding noise traced to a rear caliper, and one described the car sliding after braking on the highway. Dealers in some cases could not duplicate the concern or advised the pads were fine. Reported from roughly 40,000 to 97,000 miles in the sample, with a few reports at lower mileage.

   1 related service bulletin

   What to check: Have the brakes inspected, including rear calipers and the ABS warning light history, and ask whether any ABS-related diagnostic codes were stored or repaired.

   2 excerpts from owner complaints in NHTSA records

   “First of all I know there is a break in period. The stering seems to be loose at times almost to loose when I’m turning , especially a more sharper turn. The brakes are loud at a stop almost like they are warped but it only has 300 miles.the suspension, brakes,,underneath the front end, and the steering do not feel like they are one unit.”

   NHTSA complaint #11439954, filed 2021-11

   “I Serviced my vehicle with a Nissan Dealership, and was told brake pads were good. Within a couple of weeks there was a scratching sound like the brake warning indicator. I brought my car to a mechanic to be repaired but brake pads were confirmed to be fine. Further investigation indicates a bad brake caliper in the rear. Mechanic contacted Nissan to order a rear caliper and was told it’s a known issue with the rear calipers. …”

   NHTSA complaint #11616799, filed 2024-09
4. 4
   Engine

   Engine noise, loss of power, and debris in the oil pan

   • 8 complaints (11%)
   • median 84,500 mi at 4.5 yrs old (2 state mileage, few)
   • filed 2024–2026

   Complaints describe the engine losing power briefly or going into limp mode with the check engine light, and abnormal noises from the engine bay. Some owners had oil samples tested or the pan inspected and were told metal debris was present, with a dealer diagnosis of engine replacement in one case. Others describe stalling or a no-start condition traced to the battery or alternator. Reported from around 50,000 up to about 118,000 miles in the sample.

   What to check: Check the oil level and condition, look for a fuel smell or metallic debris on the dipstick, and ask for oil change records and whether any engine-related diagnostic codes were stored.

   2 excerpts from owner complaints in NHTSA records

   “Often while driving the car loses power as if the power went off or I ran out of gas,,, studder for a moment then pick up power to continue to drive is the best way I can describe it. Immediately after I get a notification on the dashboard saying maintenance something”

   NHTSA complaint #11744468, filed 2026-06

   “While heading west on interstate after a Drs. Appointment my wife was driving our 2021 Nissan Altima when suddenly there was a loss of power to the engine as if the engine was overheating or had loss of fuel or only able to slowly exit the freeway to a safe place and call a tow truck, after 1 1/2 days of diagnosing and testing. I was able to drive the vehicle with no issues for approximately 4000 miles when the exact problem has occurred this past Friday 6-19-2026”

   NHTSA complaint #11745511, filed 2026-06
5. 5
   Back-over prevention (rear camera)

   Rearview camera image distorts or goes blank

   • 7 complaints (10%)
   • median 49,000 mi at 3.3 yrs old (1 states mileage, few)
   • filed 2022–2026

   Owners report the backup camera showing lines, freezing, or going dark, and false rear cross-traffic or rear automatic braking warnings when nothing is behind the car. Some were told their vehicle was not covered by the camera harness recall and were offered no assistance. Others describe warnings appearing intermittently at stops or in rain. Mostly described between roughly 30,000 and 50,000 miles, and in wet weather for some owners.

   Recall 23V6280003 related service bulletins

   What to check: Put the car in reverse and check the camera display for distortion or dropout, and ask whether the camera harness recall 23V628000 was performed for this vehicle.

   2 excerpts from owner complaints in NHTSA records

   “About a month ago I noticed my backup camera had gotten dark. I didn’t worry much about it until it started glitching a couple days ago. I gave it a couple of days thinking it would go away but it hasn’t. It either glitches with lines through it, it freezes, or goes black altogether. I then did some research on it finding that there have been recalls on the 2021 nissan altima model cameras, just not mine specifically. …”

   NHTSA complaint #11661395, filed 2025-05

   “Rear Crash warning comes on when stopped at light , or when car is put in reverse and nothings there . also wiper refill warning. stays on even when full. Has been reported to dealership more than once also hear clicking at speeds over 50 mph.”

   NHTSA complaint #11671215, filed 2025-07

Buying note. Check that the AEB software updates and the camera harness recall were completed, test every door lock and the backup camera, and have a mechanic look at the brakes and engine oil before buying. Service records for driver-assistance and brake work are worth asking for.

Summary written with AI from a sample of 60 NHTSA complaints for this model year (picked at random, with complaints that state a mileage and recent ones taken first), then checked automatically against the source records. Where a problem shows a complaint count, every complaint for this model year was matched with fixed keyword rules (written with AI and tested against the sample), and the mileage, age and repair figures are calculated from those complaints; owners' figures are as stated, not verified. Other counts refer to the sample. The excerpts come from NHTSA's public complaint records and are unverified; capitalisation is normalised, NHTSA staff notes are removed, and shortened text ends with “…”. Something wrong? Request a correction.